Method and apparatus for delivering a thermal shock

ABSTRACT

The subject disclosure relates to a system and method for testing units-under-test (UUT) with a thermal shock. The thermal shock testing system can include a chamber having an inlet and an outlet, the chamber being configured to provide a thermal shock to a unit-under-test (UUT), a pump configured to fluidly connect to the inlet of the chamber and direct a temperature controlled liquid through a channel embedded in the chamber, and a boiler and a chiller fluidly connected to the pump, the temperature of the liquid being controlled by at least one valve configured to alternatively direct hot or cold fluid to the inlet of the chamber.

BACKGROUND 1. Technical Field

The subject technology provides solutions for testing units-under-testand in particular, for providing a thermal shock test to theunits-under-test.

2. Introduction

Standard high and low temperature environmental thermal shock tests areconfigured to test the capability of material structure or compositematerials to determine how the material withstands continuousenvironmental changes between extreme high temperatures and lowtemperatures. The thermal shock tests provide information regardingphysical damages, chemical changes, and operational problems that arecaused due to thermal expansion (i.e., from the heat) and contraction(i.e., from the cold) in a short period of time relative to expectedoperational timeframes. The thermal expansion and contraction caused bythe temperature change generates stress because of the differentexpansion rates of the materials within the device being tested.

Repeated stress causes accumulated fatigue, leading to various failuremodes such as cracks and rupturing at a lower strength than the staticstrength. Repeated stress tests can also cause coatings to peel andscrews to loosen. The thermal shock test is used in the automotiveindustry to simulate adaptability of units-under-test (UUT) in rapidchanges of surrounding atmospheric temperature or to provide reliabilitytest and product screening for UUT qualification and validation. Thequality of the products being tested also can be controlled through thisprocess for product improvement.

There are currently two types of thermal shock tests, air-to-air andliquid-to-liquid. The air-to-air thermal shock method is more popularlyused by placing UUTs in a test chamber, which is divided into atwo-chamber type dynamic shock and a three-chamber type static shock,according to the specificity of the UUT being tested. Theliquid-to-liquid thermal shock method applies thermal shocks to the UUTsby alternatingly immersing the UUTs into partitioned high and lowtemperature liquid mediums in separate tanks. In the liquid-to-liquidthermal shock method, very high thermal ramp rates can be achieved whencompared to the air-to-air thermal shock method. As such, theliquid-to-liquid thermal shock test is considered to be a more stringentthermal shock method than the air-to-air method in terms ofacceleration.

Conventional methods for liquid-to-liquid thermal shock are cumbersomeand inefficient. Immersion of UUTs within high and low temperaturemediums requires a hoist assembly to lift UUTs and transfer the UUTbetween high and low temperature tanks. Transferring UUTs between tanksis labor and time intensive, especially for large UUTs. To avoid damageto sensitive electrical equipment, an entirety of an outer surface ofthe UUT may require water proofing. Due to the nature of thermal shocktesting, water proofing material can become damaged resulting in thermalshock testing disruption or failure.

As such, a need exists for an apparatus and a method that can perform athermal shock test more efficiently and effectively while including thebenefits of a liquid-to-liquid thermal shock test.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain features of the subject technology are set forth in the appendedclaims. However, the accompanying drawings, which are included toprovide further understanding, illustrate disclosed aspects and togetherwith the description serve to explain the principles of the subjecttechnology. In the drawings:

FIG. 1 illustrates an example environment that includes an autonomousvehicle in communication with a remote computing system, according tosome aspects of the disclosed technology.

FIG. 2 illustrates a perspective view of an autonomous vehicle,according to some aspects of the disclosed technology.

FIG. 3A illustrates an example schematic diagrams of a thermal shocktesting system, according to some aspects of the disclosed technology.

FIG. 3B illustrates an example schematic diagrams of a thermal shocktesting system, according to some aspects of the disclosed technology.

FIG. 4 illustrates an example schematic diagrams of a thermal shocktesting system, according to some aspects of the disclosed technology.

FIG. 5 illustrates a perspective view of an example thermal shocktesting system, according to some aspects of the disclosed technology.

FIG. 6 illustrates a cross-sectional side view of a chamber of anexample thermal shock testing system, according to some aspects of thedisclosed technology.

FIG. 7 illustrates an example schematic diagram of a thermal shocktesting system, according to some aspects of the disclosed technology.

FIG. 8 illustrates an example table of components of a thermal shocktesting system, according to some aspects of the disclosed technology.

FIG. 9 illustrates an example table of parameters of a thermal shocktesting system, according to some aspects of the disclosed technology.

FIG. 10 illustrates an example thermal shock temperature profile of athermal shock testing system, according to some aspects of the disclosedtechnology.

FIG. 11 illustrates an example process for providing a thermal shock toa unit-under-test, according to some aspects of the disclosedtechnology.

FIG. 12 illustrates an example processor-based system with which someaspects of the subject technology can be implemented.

DETAILED DESCRIPTION

Various examples of the present technology are discussed in detailbelow. While specific implementations are discussed, it should beunderstood that this is done for illustration purposes only. A personskilled in the relevant art will recognize that other components andconfigurations may be used without parting from the spirit and scope ofthe present technology. In some instances, well-known structures anddevices are shown in block diagram form in order to facilitatedescribing one or more aspects. Further, it is to be understood thatfunctionality that is described as being carried out by certain systemcomponents may be performed by more or fewer components than shown.

Faster processing speeds, increased capacity and functionality, andhigher power density in autonomous vehicles (AV) produce more heat thanprior generations of automobiles. As such, higher operating temperaturescan rapidly outstrip the capability of air-based cooling systems. Higheroperating temperatures increases the risk of reliability failures.

Liquids have a high capacity for heat transfer and can remove anddissipate heat more quickly and effectively. However, such complicatedand delicate computer systems cannot simply be immersed in a liquidmedium. The liquid medium would short circuit boards and irreparablydamage the electronic computer systems. For example, a liquid-to-liquidthermal shock test cannot be conducted on an AV compute electricalcontrol unit (ECU) due to its weight load and incompatibility withliquids.

The disclosed technologies address a need in the art for improvements intesting units-under-test. In some examples, a thermal shock testingsystem can include a chamber having a plurality of walls that isconfigured to provide the thermal shock to the UUT. The system furthercan include at least one channel being embedded within at least one wallof the plurality of walls of the chamber, wherein the at least onechannel includes an inlet and an outlet. The system also can include apump being connected to the chamber and configured to provide a liquidto the inlet of the at least one channel embedded in the chamber. Thesystem can additional include a boiler connected to the pump andconfigured to provide the liquid at a high temperature. The systemfurther can include a chiller connected to the pump and configured toprovide the liquid at a low temperature. The system also can include aplurality of valves connected to the boiler and the chiller, wherein theplurality of valves is configured to control the temperature of theliquid that is pumped to the chamber.

FIG. 1 illustrates an example autonomous vehicle environment 100. Theexample autonomous vehicle environment 100 includes an autonomousvehicle 102, a remote computing system 150, and a ridesharingapplication 170. The autonomous vehicle 102, remote computing system150, and ridesharing application 170 can communicate with each otherover one or more networks, such as a public network (e.g., a publiccloud, the Internet, etc.), a private network (e.g., a local areanetwork, a private cloud, a virtual private network, etc.), and/or ahybrid network (e.g., a multi-cloud or hybrid cloud network, etc.).

The autonomous vehicle 102 can navigate about roadways without a humandriver based on sensor signals generated by sensors 104-108 on theautonomous vehicle 102. The sensors 104-108 on the autonomous vehicle102 can include one or more types of sensors and can be arranged aboutthe autonomous vehicle 102. For example, the sensors 104-108 caninclude, without limitation, one or more inertial measuring units(IMUs), one or more image sensors (e.g., visible light image sensors,infrared image sensors, video camera sensors, surround view camerasensors, etc.), one or more light emitting sensors, one or more globalpositioning system (GPS) devices, one or more radars, one or more lightdetection and ranging sensors (LIDARs), one or more sonars, one or moreaccelerometers, one or more gyroscopes, one or more magnetometers, oneor more altimeters, one or more tilt sensors, one or more motiondetection sensors, one or more light sensors, one or more audio sensors,etc. In some implementations, sensor 104 can be a radar, sensor 106 canbe a first image sensor (e.g., a visible light camera), and sensor 108can be a second image sensor (e.g., a thermal camera). Otherimplementations can include any other number and type of sensors.

The autonomous vehicle 102 can include several mechanical systems thatare used to effectuate motion of the autonomous vehicle 102. Forinstance, the mechanical systems can include, but are not limited to, avehicle propulsion system 130, a braking system 132, and a steeringsystem 134. The vehicle propulsion system 130 can include an electricmotor, an internal combustion engine, or both. The braking system 132can include an engine brake, brake pads, actuators, and/or any othersuitable componentry configured to assist in decelerating the autonomousvehicle 102. The steering system 134 includes suitable componentryconfigured to control the direction of movement of the autonomousvehicle 102 during navigation.

The autonomous vehicle 102 can include a safety system 136. The safetysystem 136 can include lights and signal indicators, a parking brake,airbags, etc. The autonomous vehicle 102 can also include a cabin system138, which can include cabin temperature control systems, in-cabinentertainment systems, etc.

The autonomous vehicle 102 can include an internal computing system 110in communication with the sensors 104-108 and the systems 130, 132, 134,136, and 138. The internal computing system 110 includes one or moreprocessors and at least one memory for storing instructions executableby the one or more processors. The computer-executable instructions canmake up one or more services for controlling the autonomous vehicle 102,communicating with remote computing system 150, receiving inputs frompassengers or human co-pilots, logging metrics regarding data collectedby sensors 104-108 and human co-pilots, etc.

The internal computing system 110 can include a control service 112configured to control operation of the vehicle propulsion system 130,the braking system 132, the steering system 134, the safety system 136,and the cabin system 138. The control service 112 can receive sensorsignals from the sensors 104-108 can communicate with other services ofthe internal computing system 110 to effectuate operation of theautonomous vehicle 102. In some examples, control service 112 may carryout operations in concert with one or more other systems of autonomousvehicle 102.

The internal computing system 110 can also include a constraint service114 to facilitate safe propulsion of the autonomous vehicle 102. Theconstraint service 116 includes instructions for activating a constraintbased on a rule-based restriction upon operation of the autonomousvehicle 102. For example, the constraint may be a restriction onnavigation that is activated in accordance with protocols configured toavoid occupying the same space as other objects, abide by traffic laws,circumvent avoidance areas, etc. In some examples, the constraintservice 114 can be part of the control service 112.

The internal computing system 110 can also include a communicationservice 116. The communication service 116 can include software and/orhardware elements for transmitting and receiving signals to and from theremote computing system 150. The communication service 116 can beconfigured to transmit information wirelessly over a network, forexample, through an antenna array or interface that provides cellular(long-term evolution (LTE), 3rd Generation (3G), 5th Generation (5G),etc.) communication.

In some examples, one or more services of the internal computing system110 are configured to send and receive communications to remotecomputing system 150 for reporting data for training and evaluatingmachine learning algorithms, requesting assistance from remote computingsystem 150 or a human operator via remote computing system 150, softwareservice updates, ridesharing pickup and drop off instructions, etc.

The internal computing system 110 can also include a latency service118. The latency service 118 can utilize timestamps on communications toand from the remote computing system 150 to determine if a communicationhas been received from the remote computing system 150 in time to beuseful. For example, when a service of the internal computing system 110requests feedback from remote computing system 150 on a time-sensitiveprocess, the latency service 118 can determine if a response was timelyreceived from remote computing system 150, as information can quicklybecome too stale to be actionable. When the latency service 118determines that a response has not been received within a thresholdperiod of time, the latency service 118 can enable other systems ofautonomous vehicle 102 or a passenger to make decisions or provideneeded feedback.

The internal computing system 110 can also include a user interfaceservice 120 that can communicate with cabin system 138 to provideinformation or receive information to a human co-pilot or passenger. Insome examples, a human co-pilot or passenger can be asked or requestedto evaluate and override a constraint from constraint service 114. Inother examples, the human co-pilot or passenger may wish to provide aninstruction to the autonomous vehicle 102 regarding destinations,requested routes, or other requested operations.

As described above, the remote computing system 150 can be configured tosend and receive signals to and from the autonomous vehicle 102. Thesignals can include, for example and without limitation, data reportedfor training and evaluating services such as machine learning services,data for requesting assistance from remote computing system 150 or ahuman operator, software service updates, rideshare pickup and drop offinstructions, etc.

The remote computing system 150 can include an analysis service 152configured to receive data from autonomous vehicle 102 and analyze thedata to train or evaluate machine learning algorithms for operating theautonomous vehicle 102. The analysis service 152 can also performanalysis pertaining to data associated with one or more errors orconstraints reported by autonomous vehicle 102.

The remote computing system 150 can also include a user interfaceservice 154 configured to present metrics, video, images, soundsreported from the autonomous vehicle 102 to an operator of remotecomputing system 150, maps, routes, navigation data, notifications, userdata, vehicle data, software data, and/or any other content. Userinterface service 154 can receive, from an operator, input instructionsfor the autonomous vehicle 102.

The remote computing system 150 can also include an instruction service156 for sending instructions regarding the operation of the autonomousvehicle 102. For example, in response to an output of the analysisservice 152 or user interface service 154, instructions service 156 canprepare instructions to one or more services of the autonomous vehicle102 or a co-pilot or passenger of the autonomous vehicle 102.

The remote computing system 150 can also include a rideshare service 158configured to interact with ridesharing applications 170 operating oncomputing devices, such as tablet computers, laptop computers,smartphones, head-mounted displays (HMDs), gaming systems, servers,smart devices, smart wearables, and/or any other computing devices. Insome cases, such computing devices can be passenger computing devices.The rideshare service 158 can receive from passenger ridesharing app 170requests, such as user requests to be picked up or dropped off, and candispatch autonomous vehicle 102 for a requested trip.

The rideshare service 158 can also act as an intermediary between theridesharing app 170 and the autonomous vehicle 102. For example,rideshare service 158 can receive from a passenger instructions for theautonomous vehicle 102, such as instructions to go around an obstacle,change routes, honk the horn, etc. The rideshare service 158 can providesuch instructions to the autonomous vehicle 102 as requested.

The remote computing system 150 can also include a package service 162configured to interact with the ridesharing application 170 and/or adelivery service 172 of the ridesharing application 170. A useroperating ridesharing application 170 can interact with the deliveryservice 172 to specify information regarding a package to be deliveredusing the autonomous vehicle 102. The specified information can include,for example and without limitation, package dimensions, a packageweight, a destination address, delivery instructions (e.g., a deliverytime, a delivery note, a delivery constraint, etc.), and so forth.

The package service 162 can interact with the delivery service 172 toprovide a package identifier to the user for package labeling andtracking. Package delivery service 172 can also inform a user of whereto bring their labeled package for drop off. In some examples, a usercan request the autonomous vehicle 102 come to a specific location, suchas the user's location, to pick up the package. While delivery service172 has been shown as part of the ridesharing application 170, it willbe appreciated by those of ordinary skill in the art that deliveryservice 172 can be its own separate application.

One beneficial aspect of utilizing autonomous vehicle 102 for bothridesharing and package delivery is increased utilization of theautonomous vehicle 102. Instruction service 156 can continuously keepthe autonomous vehicle 102 engaged in a productive itinerary betweenrideshare trips by filling what otherwise would have been idle time withproductive package delivery trips.

Embodiments include an apparatus and a method that perform a thermalshock test such that the unit-under-test (UUT) (e.g., a computer or anautonomous vehicle (AV) component) can function during and after abruptand rapid fluctuations in temperature without experiencing degradationand loss in function.

FIG. 2 illustrates a perspective view of an autonomous vehicle,according to some aspects of the disclosed technology. FIG. 2 furtherillustrates 3D axes including a Z-axis (up/down/vertical), an X-axis(fwd/aft/longitudinal), and a Y-axis (left/right/lateral).

UUT Placement Orientation:

UUT's in-test placement can mimic in-vehicle orientation, mountingcondition, and frequency response characteristics. For example, in AVcompute testing, UUTs can be placed approximately 19 degrees along thevertical Z-axis direction.

Inspection and Measurement for Reliability Testing:

UUTs can proceed through diagnostic checks including functional andcosmetic inspections before, during, and after testing to measuredegradation in performance or catastrophic failures.

Cosmetic inspection can include visually inspecting the UUT forvariations in plastic and metal color, surface finish, gaps betweenadjacent features, signs of cracking, rupturing, screw loosening,deformation, warpage, corrosion, delamination, scratches, dents, bulges,bubbles, peeling, and any other variation suitable for the intendedpurpose and understood by a person of ordinary skill in the art.

Functional Test can include a functional/parametric check to determinewhether the UUT is functional. Functionality of input/output (I/O)connectors and mechanical moving parts can be checked.

Dimensional checks can include performing a visual inspection andmeasuring gap/flush dimensions using a coordinate measuring machine(CMM) or a pair of calipers.

Pass/Fail Criteria:

The UUT can be considered as “passing” if it meets cosmetic,dimensional, and functionality requirements during the test. Forexample, functional failures and mechanical damage are typically notallowed. In other embodiments, a certain level of cosmetic damage and/ordimensional change can be acceptable pending on an engineering riskassessment.

Reliability Test Report:

A reliability engineer also can provide a test report template that canbe used as an overall summary of the test results. The reliabilityengineer executing the reliability test plan can generate data sheets todocument objective and subjective data collected throughout the test.Updated reports can be sent to the reliability engineer every week ormore frequently as test milestones are reached. All results can bereported as numerical values whenever possible. Test reports caninclude:

-   -   1) Results of pre-test, mid-test, and post-test cosmetic        inspections, dimensional checks, and functional test logs.        Pictures of cosmetic anomalies and dimensional changes also can        be included.    -   2) Report pass/fail status of samples.    -   3) Photographs of the test setup including photos of the sample        orientation in the chamber or dynamic fixture.    -   4) Photograph the sample before and after each test procedure.    -   5) Chamber logs (e.g., temperature and humidity as-run        profiles).

FIGS. 3A-6 illustrate example schematic diagrams and perspective viewsof an example thermal shock testing system 300, according to someaspects of the disclosed technology.

Reliability Test Procedure and Requirements:

Embodiments of the thermal shock testing system 300 can include achiller 302 (with cold coolant), a chiller/boiler 304 (with warmcoolant), a chamber 306, and a coldplate 308 or a thermally sealed box.In some instances, the thermal shock testing system 300 also can includecirculating, alternatingly, cold coolant from the chiller 302 and warmcoolant from the boiler 304 through the coldplate 308 to form a fasttemperature change environment within the enclosure/chamber 306. Such atemperature change environment induced by the cold and hot coolants canmimic a field condition more realistically. In addition to thetemperature change, internal pressures of the liquid pipe and the heatpipe can be cyclically changed due to the fast temperature change.

Example schematic and perspective setups of the liquid-to-liquid thermalshock testing system 300 are illustrated in FIGS. 3A-6 along with ahot/cold liquid input control algorithm. For example, a thermal cycling(dT) of −25 degrees Celsius to 85 degrees Celsius or larger dT can beused for testing solder joints, PCBs, and electrical connections. Theminimum and maximum temperature values can be modified depending on theUUT and at the discretion of the reliability engineer.

In some instances, the thermal shock testing system 300 can include achamber 306 having an inlet 310, an outlet 312, and a coldplate 308, aplurality of valves 314, a pump 316, a chiller (cold) 302, and a chiller(hot) 304. The chamber 306 can include a plurality of walls including atop wall 318, a bottom wall 320, and sidewalls 322. In some instances,the bottom wall 320 can be the coldplate 308.

In other instances, the chamber 306 and/or the coldplate 308 of thethermal shock testing system 300 can include at least one channel 324that facilitates the cold/hot liquid to flow from the inlet 310 to theoutlet 312 of the thermal shock testing system 300. The at least onechannel 324 can be a channel, a cavity, a tube, a coil, a thermal coilor any other channel suitable for the intended purpose and understood bya person of ordinary skill in the art.

The thermal shock testing system 300 can further include a plurality ofchannels 324 in the plurality of walls 318, 320, 322 of the chamber 306and the coldplate 308 with corresponding inlets 310 and outlets 312 toprovide various temperature regions throughout the walls 318, 320, 322of the chamber 306 and the coldplate 308, as shown in FIG. 5 . In somecases, the channels 324 can form thermal coils 326 in various regions ofthe chamber 306 and the coldplate 308. The thermal coils 326 can beplanar (as illustrated in FIG. 5 ) or non-planar to the walls 318, 320,322 of the chamber 306 and the coldplate 308. For example, in FIG. 5 ,two thermal coils 326 are provided in one side wall 322, while onethermal coil is provided in another side wall 322 and the bottom wall320/coldplate 308. In other instances, different configurationsincluding thermal coils 326 in the top wall 318 of the chamber 306 and avarying number of thermal coils 326 in the plurality of walls 318, 320,322 and the coldplate 308 are contemplated in this disclosure. Variousquadrants of the walls 318, 320, 322 of the chamber 306 and/or thecoldplate 308 can also have different temperatures based on thearrangement of the plurality of channels 324 in the system 300 so that asingle UUT or multiple UUTs can experience different temperatures at thesame time.

The thermal shock testing system 300 also can be a “chamber in achamber” thermal shock testing system 300. For example, one chamber 306can be positioned within another chamber 306 such that both chambers 306are capable of providing a thermal shock test to a UUT. The coldplate308 can serve as an independent thermal shock chamber to test the UUT,while also being inside the chamber 306 having an alternating cold andhot liquid circulation. Heat can be transferred by the liquid, insteadof by the air, without having to move the UUT. The chamber 306 of thethermal shock testing system 300 can be an outer environmental chamberthat includes an independent temperature control that can mimic a carbeing outside use-type environment.

In further instances, the thermal shock testing system 300 can furtherinclude a flow meter (FM) 328 to determine the flow rate of the liquidin the thermal shock testing system 300.

In some instances, a temperature transducer (T) 330 and a pressuretransducer (P) 332 can be positioned at an inlet of a source connector334 and at an outlet of a return connector 336 of a device-under-test(DUT) of the thermal shock testing system 300. The DUT may be similar toor the same as the UUT.

In other instances, the plurality of valves 314 of the thermal shocktesting system 300 can include a hot source valve 338, a hot returnvalve 340, a cold source valve 342, and a cold return valve 344. Thethermal shock testing system 300 also can include a bypass valve 346that can be positioned between the input of the temperature transducer330 and pressure transducer 332 of the source connector 334 and theoutput of the temperature transducer 330 and pressure transducer 332 ofthe return connector 336. The bypass valve 346 can maintain thetemperature in piping when the DUT is not connected, which can allowcontinuous running of the chillers 302, 304 to maximize up-time.

In another instance, the thermal shock testing system 300 can include anin-line filter 348 at the DUT return along with a different pressuresensor (dP) 332 to evaluate when the system 300 is clogged.

In some embodiments, fasteners can be used to secure the DUT to thechamber 306/coldplate 308 of the thermal shock testing system 300. Forexample, the fasteners can be used along a perimeter of the DUT tosecure the DUT in a particular location of the chamber 306/coldplate308. The fasteners can include magnets, latches, inserts, screws, tiedowns, or any other fastener suitable for the intended purpose andunderstood by a person of ordinary skill in the art. Furthermore, thefasteners may be repositionable along the chamber 306/coldplate 308 ofthe thermal shock testing system 300. For example, if the DUT is to bepositioned in a different position, the fasteners can be moved to securethe DUT in the new position. Moreover, if a new DUT is to be tested, thefasteners can be repositioned to the perimeter of the new DUT. In someinstances, the DUT can be placed on top of the fasteners depending onthe testing parameters.

In other instances, the fasteners of the thermal shock testing systemcan be pedestals 350 as shown in FIG. 6 . The pedestals 350 can beconfigurable, thermally conductive pedestals that are positionablewithin the interior portion of the coldplate 308/chamber 306 of thethermal shock testing system 300. The pedestals 350 further can beindependent of the coldplate 308/chamber 306 of the thermal shocktesting system 300. The thermally conductive pedestals 350 can be madeof metals with high thermal conductivity such as aluminum, copper,brass, steel, bronze, or any other metal with high thermal conductivitythat is suitable for the intended purpose and understood by a person ofordinary skill in the art.

In some instances, a DUT can include “hot” components that areoperational and that are positioned on a substrate, printed circuitboard (PCB), or a motherboard. The substrate or motherboard can bethermally connected to the coldplate 308 or the bottom plate of thechamber 306 of the thermal shock testing system 300. Furthermore, thepedestals 350 can thermally connect the plate wall (e.g., top plate 318or side walls 322) of the chamber 306 to the surfaces of the “hot”components of the DUT that are positioned on the substrate/motherboardto provide a secondary path of thermal distribution.

Furthermore, the pedestals 350 can be positioned adjacent to “hot”components (e.g., one or more processors) as targeted components asshown in FIG. 6 . The targeted components typically produce a greaterthermal output than other components on the motherboard when thecomponents are operating in their normal capacity. By targeting “hot”components on the substrate/motherboard with the pedestals 350,components having a greater thermal range during operation are subjectto a greater thermal range during a thermal shock test. Thus, bytargeting “hot” components, the thermal shock testing system 300 canmore accurately simulate a thermal stress that the DUT experiencesduring operation than conventional thermal stress techniques.

In some instances, the liquid-to-liquid thermal shock testing system 300can be coupled with a liquid cooling system (LCS) 352, which can beintegrated with a unit-under-test (UUT) 354, as shown in FIG. 3B. Forexample, the liquid-to-liquid thermal shock testing system 300 can beconfigured to couple with the LCS 352, which can be integrated into anouter casing 356 of the UUT 354.

The outer casing 356 of the UUT 354 can include channels (similar to thechannels 324) that can be embedded within and traverse throughout theouter casing 356 of the UUT 354. The channels of the LCS 352 can befluidly coupled to the channels 324 of the liquid-to-liquid thermalshock testing system 300 such that the temperature regulated fluid fromthe liquid-to-liquid thermal shock testing system 300 can be utilized bythe channels of the LCS 352. In some instances, the liquid-to-liquidthermal shock testing system 300 can be fluidly coupled to an inlet 310and an outlet 312 of the LCS 352. As provided above, theliquid-to-liquid thermal shock testing system 300 can direct temperatureregulated fluid into the LCS 352 to conduct a thermal shock test oncomponents adjacent to coldplate(s) 308.

In other instances, the channels of the LCS 352 further can be proximate(e.g., adjacent) to the coldplate(s) 308 to regulate the coldplate(s)308. An interior portion of a wall of the outer casing 356 can includeone or more coldplate(s) (e.g., the coldplate 308). In some cases, theinterior region within the outer casing 356 can be or include thechamber 306 of the liquid-to-liquid thermal shock testing system 300.Furthermore, the coldplate(s) 308 can be proximate (e.g., adjacent) tocomponents of a computer (e.g., one or more processors).

The LCS 352 also can house and thermally regulate electrical components,processors, memory, or any other component suitable for the intendedpurpose and understood by a person of ordinary skill in the art. Thethermal shock testing system 300 of the LCS 352 not only can provide athermal shock test to components, the LCS 352 can also thermallyregulate the UUT 354 by controlling the temperature of the liquidpassing through the channels 324 of the thermal testing system 300 andthe channels of the LCS 352, and by utilizing the thermal conductiveproperties of the pedestals 350.

In some cases, the LCS 352 can comprise optimized system components,such as pumps 316, cold plates 308, pedestals 350, and heat pipes 324that may be pre-configured to cool high-power density devices of anautonomous vehicle. For example, the LCS 352 can include cold plates 308that are proximate to key components within a UUT/DUT as shown in FIG. 6. By leveraging the LCS 352 to perform the liquid-to-liquid thermalshock test, key components within the UUT/DUT can be more directlytargeted than with conventional liquid-to-liquid cooling testtechniques.

In some instances, the LCS 352 can be utilized to cool a compute duringnormal operation (i.e., when the computer is running during AVoperation). The LCS 352 can include piping/channels that are integratedin the casing/walls 318, 320, 322 of the compute. The casing of thecompute can include conductive layers (e.g., pedestals 350 as shown inFIG. 6 ) that can be positioned proximate to components (e.g., “hot”processors) on one side and in contact with the casing havingpiping/channels on the other side. Thus, during normal operation, theLCS 352 can maintain the components at an optimal or selectedtemperature range.

Thermal interface material or soldering can be utilized to facilitatethe thermal connection between the pedestals 350 and the DUT to improvea temperature transition of the DUT that is positioned within theinterior portion of the coldplate 308/chamber 306 of the thermal shocktesting system 300. Examples of the thermal interface material caninclude a thermal grease, a thermal adhesive, a thermal gap filler, athermally conductive pad, thermal tape, phase-change materials, or anyother thermal interface material suitable for the intended purpose andunderstood by a person of ordinary skill in the art.

FIG. 7 illustrates an example schematic diagram of a thermal shocktesting system, according to some aspects of the disclosed technology.

In some instances, similar to the thermal shock testing system 300 ofFIG. 4 , a thermal shock testing system 700 can include a chiller 402, afeed pump 404, a heater 406, temperature 408 and pressure 410implementation (e.g., transducers), a 2-way motor controlled valve 412,a 3-way motor controlled valve 414, a centrifugal circulation pump 416,a 3-way bypass valve 418, a bypass/relief service valve 420, and apressure relief valve 422.

In some instances, the chiller 402, the temperature 408 and pressure 410instrumentation, and the centrifugal pump 416 can be combined with acold water tank 424 to form a cooling system 430. In other instances,the heater 406, the temperature 408 and pressure 410 instrumentation,and the centrifugal pump 416 can be combined with a hot water tank 426to form a heating system 432.

The fluid from the chiller 402 and the heater 406 can flow through the3-way motor controlled valve 414 into the feed pump 404. The fluid canthen flow through the bypass/relief service valve 420 or the pressurerelief valve 422 and through the 3-way bypass valve 418. The fluid canthen flow through another temperature 408 and pressure 410instrumentation and into an input of a plate 428. From the output of theplate 428, the fluid can flow through a different temperature 408 andpressure 410 instrumentation, through the 2-way motor controlled valves412, and into the cooling system 430/heating system 432.

FIG. 8 illustrates an example table of components of a thermal shocktesting system 300, 400, according to some aspects of the disclosedtechnology. In some instances, a power on/off temperature difference canbe a factor that drives a temperature change impact on the components onthe compute board (e.g., UUT). Some of the equipment parts/components ofthe LCS liquid-to-liquid thermal shock testing system 300, 400 arelisted in the table of FIG. 8 . The chiller (cold) 302 can provide atemperature range approximately between −25 degrees Celsius and 15degrees Celsius. The chiller (hot) 304 can provide a temperature rangeapproximately between 25 degrees Celsius and 90 degrees Celsius. Thevalves 314 can provide/tolerate a temperature range approximatelybetween −25 degrees Celsius and 95 degrees Celsius. The chamber 306(e.g., an environmental chamber) can tolerate a temperature rangeapproximately between −25 degrees Celsius and 125 degrees Celsius. Thechamber 306 also can include dry nitrogen purging gas capabilities tominimize surface condensation. The thermal shock testing system 300, 400also can include a pressure transducer 332 (e.g., 0-1 MPa). The thermalshock testing system 300, 400 can further include a temperaturetransducer 330 (e.g., −50 degrees Celsius to 120 degrees Celsius).

FIG. 9 illustrates an example table of parameters of a thermal shocktesting system 300, 400, according to some aspects of the disclosedtechnology. An example of thermal shock testing parameters is shown inFIG. 9 , which include a temperature range between −20 degrees Celsiusand 85 degrees Celsius. The temperature range can be modified to besuitable for the intended purpose and understood by a person of ordinaryskill in the art.

In some embodiments, the thermal shock testing system parameters caninclude 50 cycles, a maximum temperature of 85 degrees Celsius, aminimum temperature of −25 degrees Celsius, a ramp rate of less than 10seconds, a dwell time of 30 minutes at the maximum temperature and theminimum temperature, a UUT ambient temperature between −20 degreesCelsius and 50 degrees Celsius, and a UUT power on/off option.

In some instances, the chamber 306 of the thermal shock testing system300 can include a dry nitrogen purging gas to provide a non-condensingtransition from one test level (e.g., temperature) to another. Thepurging gas also can be carbon dioxide or any other purging gas suitablefor the intended purpose and understood by a person of ordinary skill inthe art to sustain a non-condensing environment during the thermal shocktest for a non-frost thermal shock. If a frost condition is needed as anadditional condensation test parameter (in parallel with the thermalshock), the dry nitrogen purging gas may not be used. As such, in someinstances, the thermal shock testing system 300, 400 can include twoliquid-to-liquid thermal shock tests, one without surface condensationand one with surface condensation.

FIG. 10 illustrates an example thermal shock temperature profile of athermal shock testing system 300, 400, according to some aspects of thedisclosed technology. An example test procedure is provided below:

Liquid-to-liquid non-operational or operational thermal shock withoutUUT surface condensation:

-   -   1) Perform a functional, cosmetic, and dimensional inspection of        the UUT.    -   2) Place the UUT in the chamber 306 of the thermal shock testing        system 300, 400, set the chamber temperature to 25 degrees        Celsius with uncontrolled humidity, and start nitrogen gas (N2)        purging.    -   3) Set the chiller 302, 402 to the desired temperature (Tmin)        and the boiler 304, 406 to the desired temperature (Tmax).    -   4) Begin cycling at room temperature. Turn on the hot coolant        valve 314, 414.    -   5) Allow the UUT to dwell at the high temperature (85 degrees        Celsius) for the set dwell time (30 minutes).    -   6) Turn off the hot coolant valve 314, 414 and turn on the cold        coolant valve 314, 414 (ramp rate of less than 11 degrees        Celsius/second).    -   7) Allow the UUT to dwell at the low temperature (−25 degrees        Celsius) for the set dwell time (30 minutes).    -   8) Repeat steps 4 through 7 for the set number of cycles.    -   9) Perform a baseline functional, cosmetic, and dimensional        inspection to determine whether any changes or abnormalities        occurred during the thermal shock test.

Liquid-to-liquid operational thermal shock without UUT surfacecondensation:

-   -   1) Perform a baseline functional, cosmetic, and dimensional        inspection of the UUT.    -   2) Install a thermocouple at the specific component location, if        required.    -   3) Place the UUT in the chamber 306 of the thermal shock testing        system 300, 400, set the chamber temperature to 25 degrees        Celsius with uncontrolled humidity, and start nitrogen gas (N2)        purging.    -   4) Boot the UUT and start diagnostic software. Allow the UUT to        successfully pass 2 complete cycles of the diagnostics before        continuing. Continue running the diagnostic software during the        entire thermal shock cycle.    -   5) Set the chiller 302, 402 to the desired temperature (Tmin)        and the boiler 304, 406 to the desired temperature (Tmax).    -   6) Begin cycling at room temperature. Turn on the hot coolant        valve 314, 414.    -   7) Allow the UUT to dwell at the high temperature (85 degrees        Celsius) for the set dwell time (30 minutes).    -   8) Turn off the hot coolant valve 314, 414 and turn on the cold        coolant valve 314, 414 (ramp rate of less than 11 degrees        Celsius/second).    -   9) Allow the UUT to dwell at the low temperature (−25 degrees        Celsius) for the set dwell time (30 minutes).    -   10) Repeat steps 5 through 9 for the number of cycles. Monitor        the UUT to determine if the diagnostic software reports any        failures.    -   11) Perform a baseline functional, cosmetic, and dimensional        inspection to determine whether any changes or abnormalities        occurred during the thermal shock test.

Having disclosed some example system components and concepts, thedisclosure now turns to FIG. 11 , which illustrate example method 1100for providing a thermal shock to a unit-under-test. The steps outlinedherein are exemplary and can be implemented in any combination thereof,including combinations that exclude, add, or modify certain steps.

The thermal shock testing system can include a computer-implementedcontrol algorithm for directing the coolant hot and cold thermal shock.The computer-implemented control algorithm can include switching to ahot loop, turning on a pump, turning the pump off when a target time hasbeen reached, switching to a cold loop, turning on the pump, turning thepump off when a target time has been reached, and repeating the abovesteps until a specified target number of cycles has been reached.

At step 1102, the method 1100 can include providing a thermal testingsystem to test a unit-under-test (UUT) with a thermal shock. Forexample, providing a thermal testing system comprising: a chamber havingan inlet and an outlet, the chamber being configured to provide athermal shock to a unit-under-test (UUT), a pump configured to fluidlyconnect to the inlet of the chamber and direct a temperature controlledliquid through a channel embedded in the chamber, and a boiler and achiller fluidly connected to the pump, the temperature of the liquidbeing controlled by at least one valve configured to alternativelydirect hot or cold fluid to the inlet of the chamber.

At step 1104, the method 1100 can include positioning the UUT into aninterior portion of the chamber.

At step 1106, the method 1100 can include setting the boiler to a hightemperature and the chiller to a low temperature.

At step 1108, the method 1100 can include opening the at least one valveto heat the UUT with the hot fluid.

At step 1110, the method 1100 can include dwelling the UUT at the hightemperature for a first dwell time.

At step 1112, the method 1100 can include closing the at least one valveto chill the UUT with the cold fluid within a ramp rate.

At step 1114, the method 1100 can include dwelling the UUT at the lowtemperature for a second dwell time.

The method 1100 also can include booting the UUT and starting adiagnostic test to monitor the UUT during the thermal shock test. Themethod 1100 further can include the ramp rate being approximately 11degrees Celsius per second. The method 1100 additionally can include thefirst dwell time and the second dwell time being approximately 30minutes.

In some instances, the method 1100 can further include the chamber beingconfigured to receive the UUT. The channel can be embedded within anouter casing surrounding the chamber. The chamber can be within an outercasing of a liquid cooling system of an autonomous vehicle. The UUT canbe a compute of an autonomous vehicle. The thermal testing system canfurther comprise: a first temperature transducer and a first pressuretransducer that are connected to the inlet of the chamber, and a secondtemperature transducer and a second pressure transducer that areconnected to the outlet of the chamber. The thermal testing system canfurther comprise a bypass valve between the inlet and the outlet of thechamber to maintain the temperature in the channel when the UUT is notconnected to the chamber. The hot fluid can be approximately 85 degreesCelsius and the cold fluid is approximately −25 degrees Celsius. Thethermal testing system can further comprises a plurality of channels, afirst channel of the plurality of channels including a first coilconfigured to adjust a temperature of a first portion of the chamber,and a second channel of the plurality of channels including a secondcoil configured to adjust a temperature of a second portion of thechamber. The first coil of the first channel can provide a differenttemperature than the second coil of the second channel.

FIG. 12 illustrates an example computing system 1200 which can be, forexample, any computing device making up internal computing system 110,remote computing system 150, a passenger device executing rideshareapplication 170, or any other computing device. In FIG. 12 , thecomponents of the computing system 1200 are in communication with eachother using connection 1205. Connection 1205 can be a physicalconnection via a bus, or a direct connection into processor 1210, suchas in a chipset architecture. Connection 1205 can also be a virtualconnection, networked connection, or logical connection.

In some embodiments, computing system 1200 is a distributed system inwhich the functions described in this disclosure can be distributedwithin a datacenter, multiple data centers, a peer network, etc. In someembodiments, one or more of the described system components representsmany such components each performing some or all of the function forwhich the component is described. In some embodiments, the componentscan be physical or virtual devices.

Example system 1200 includes at least one processing unit (CPU orprocessor) 1210 and connection 1205 that couples various systemcomponents including system memory 1215, such as read-only memory (ROM)1220 and random access memory (RAM) 1225 to processor 1210. Computingsystem 1200 can include a cache of high-speed memory 1212 connecteddirectly with, in close proximity to, or integrated as part of processor1210.

Processor 1210 can include any general purpose processor and a hardwareservice or software service, such as services 1232, 1234, and 1236stored in storage device 1230, configured to control processor 1210 aswell as a special-purpose processor where software instructions areincorporated into the actual processor design. Processor 1210 mayessentially be a completely self-contained computing system, containingmultiple cores or processors, a bus, memory controller, cache, etc. Amulti-core processor may be symmetric or asymmetric.

To enable user interaction, computing system 1200 includes an inputdevice 1245, which can represent any number of input mechanisms, such asa microphone for speech, a touch-sensitive screen for gesture orgraphical input, keyboard, mouse, motion input, speech, etc. Computingsystem 1200 can also include output device 1235, which can be one ormore of a number of output mechanisms known to those of skill in theart. In some instances, multimodal systems can enable a user to providemultiple types of input/output to communicate with computing system1200. Computing system 1200 can include communications interface 1240,which can generally govern and manage the user input and system output.There is no restriction on operating on any particular hardwarearrangement, and therefore the basic features here may easily besubstituted for improved hardware or firmware arrangements as they aredeveloped.

Storage device 1230 can be a non-volatile memory device and can be ahard disk or other types of computer readable media which can store datathat are accessible by a computer, such as magnetic cassettes, flashmemory cards, solid state memory devices, digital versatile disks,cartridges, random access memories (RAMs), read-only memory (ROM),and/or some combination of these devices.

The storage device 1230 can include software services, servers,services, etc., that when the code that defines such software isexecuted by the processor 1210, it causes the system to perform afunction. In some embodiments, a hardware service that performs aparticular function can include the software component stored in acomputer-readable medium in connection with the necessary hardwarecomponents, such as processor 1210, connection 1205, output device 1235,etc., to carry out the function.

For clarity of explanation, in some instances, the present technologymay be presented as including individual functional blocks includingfunctional blocks comprising devices, device components, steps orroutines in a method embodied in software, or combinations of hardwareand software.

Any of the steps, operations, functions, or processes described hereinmay be performed or implemented by a combination of hardware andsoftware services or services, alone or in combination with otherdevices. In some embodiments, a service can be software that resides inmemory of a client device and/or one or more servers of a contentmanagement system and perform one or more functions when a processorexecutes the software associated with the service. In some embodiments,a service is a program or a collection of programs that carry out aspecific function. In some embodiments, a service can be considered aserver. The memory can be a non-transitory computer-readable medium.

In some embodiments, the computer-readable storage devices, mediums, andmemories can include a cable or wireless signal containing a bit streamand the like. However, when mentioned, non-transitory computer-readablestorage media expressly exclude media such as energy, carrier signals,electromagnetic waves, and signals per se.

Methods according to the above-described examples can be implementedusing computer-executable instructions that are stored or otherwiseavailable from computer-readable media. Such instructions can comprise,for example, instructions and data which cause or otherwise configure ageneral purpose computer, special purpose computer, or special purposeprocessing device to perform a certain function or group of functions.Portions of computer resources used can be accessible over a network.The executable computer instructions may be, for example, binaries,intermediate format instructions such as assembly language, firmware, orsource code. Examples of computer-readable media that may be used tostore instructions, information used, and/or information created duringmethods according to described examples include magnetic or opticaldisks, solid-state memory devices, flash memory, USB devices providedwith non-volatile memory, networked storage devices, and so on.

Devices implementing methods according to these disclosures can comprisehardware, firmware and/or software, and can take any of a variety ofform factors. Typical examples of such form factors include servers,laptops, smartphones, small form factor personal computers, personaldigital assistants, and so on. The functionality described herein alsocan be embodied in peripherals or add-in cards. Such functionality canalso be implemented on a circuit board among different chips ordifferent processes executing in a single device, by way of furtherexample.

The instructions, media for conveying such instructions, computingresources for executing them, and other structures for supporting suchcomputing resources are means for providing the functions described inthese disclosures.

Although a variety of examples and other information was used to explainaspects within the scope of the appended claims, no limitation of theclaims should be implied based on particular features or arrangements insuch examples, as one of ordinary skill would be able to use theseexamples to derive a wide variety of implementations. Further andalthough some subject matter may have been described in languagespecific to examples of structural features and/or method steps, it isto be understood that the subject matter defined in the appended claimsis not necessarily limited to these described features or acts. Forexample, such functionality can be distributed differently or performedin components other than those identified herein. Rather, the describedfeatures and steps are disclosed as examples of components of systemsand methods within the scope of the appended claims.

Claim language reciting “at least one of” a set indicates that onemember of the set or multiple members of the set satisfy the claim. Forexample, claim language reciting “at least one of A and B” means A, B,or A and B.

What is claimed is:
 1. A thermal testing system comprising: a chamberhaving an inlet and an outlet, the chamber being configured to provide athermal shock to a unit-under-test (UUT); a pump configured to fluidlyconnect to the inlet of the chamber and direct a temperature controlledliquid through a channel embedded in the chamber; and a boiler and achiller fluidly connected to the pump, the temperature of the liquidbeing controlled by at least one valve configured to alternativelydirect hot or cold fluid to the inlet of the chamber.
 2. The thermaltesting system of claim 1, wherein the chamber is configured to receivethe UUT.
 3. The thermal testing system of claim 1, wherein the channelis embedded within an outer casing surrounding the chamber.
 4. Thethermal testing system of claim 1, wherein the chamber is within anouter casing of a liquid cooling system of an autonomous vehicle.
 5. Thethermal testing system of claim 1, wherein the UUT is a compute of anautonomous vehicle.
 6. The thermal testing system of claim 1, furthercomprising: a first temperature transducer and a first pressuretransducer that are connected to the inlet of the chamber; and a secondtemperature transducer and a second pressure transducer that areconnected to the outlet of the chamber.
 7. The thermal testing system ofclaim 1, further comprising a bypass valve between the inlet and theoutlet of the chamber to maintain the temperature in the channel whenthe UUT is not connected to the chamber.
 8. The thermal testing systemof claim 1, wherein the hot fluid is approximately 85 degrees Celsiusand the cold fluid is approximately −25 degrees Celsius.
 9. The thermaltesting system of claim 1, further comprising a plurality of channels, afirst channel of the plurality of channels including a first coilconfigured to adjust a temperature of a first portion of the chamber,and a second channel of the plurality of channels including a secondcoil configured to adjust a temperature of a second portion of thechamber.
 10. The thermal testing system of claim 9, wherein the firstcoil of the first channel provides a different temperature than thesecond coil of the second channel.
 11. A method comprising: providing athermal testing system comprising: a chamber having an inlet and anoutlet, the chamber being configured to provide a thermal shock to aunit-under-test (UUT); a pump configured to fluidly connect to the inletof the chamber and direct a temperature controlled liquid through achannel embedded in the chamber; and a boiler and a chiller fluidlyconnected to the pump, the temperature of the liquid being controlled byat least one valve configured to alternatively direct hot or cold fluidto the inlet of the chamber; positioning the UUT into an interiorportion of the chamber; setting the boiler to a high temperature and thechiller to a low temperature; opening the at least one valve to heat theUUT with the hot fluid; dwelling the UUT at the high temperature for afirst dwell time; closing the at least one valve to chill the UUT withthe cold fluid within a ramp rate; and dwelling the UUT at the lowtemperature for a second dwell time.
 12. The method of claim 11, whereinthe chamber is configured to receive the UUT.
 13. The method of claim11, wherein the channel is embedded within an outer casing surroundingthe chamber.
 14. The method of claim 11, wherein the chamber is withinan outer casing of a liquid cooling system of an autonomous vehicle. 15.The method of claim 11, wherein the UUT is a compute of an autonomousvehicle.
 16. The method of claim 11, wherein the thermal testing systemfurther comprises: a first temperature transducer and a first pressuretransducer that are connected to the inlet of the chamber; and a secondtemperature transducer and a second pressure transducer that areconnected to the outlet of the chamber.
 17. The method of claim 11,wherein the thermal testing system further comprises a bypass valvebetween the inlet and the outlet of the chamber to maintain thetemperature in the channel when the UUT is not connected to the chamber.18. The method of claim 11, wherein the hot fluid is approximately 85degrees Celsius and the cold fluid is approximately −25 degrees Celsius.19. The method of claim 11, wherein the thermal testing system furthercomprises a plurality of channels, a first channel of the plurality ofchannels including a first coil configured to adjust a temperature of afirst portion of the chamber, and a second channel of the plurality ofchannels including a second coil configured to adjust a temperature of asecond portion of the chamber.
 20. The method of claim 19, wherein thefirst coil of the first channel provides a different temperature thanthe second coil of the second channel.